html,body {
            height: 100%;
        }

.body {
     display: flex;
     flex-direction: column;
}

.header{
    background-color: #fff;
    font-size: 16px;
    height: 44px;
    line-height: 44px;
    text-align: center;
}
.main{
    background: url(../img/advertisement-bg.jpg) no-repeat;
    background-position: center top;
    background-size: 1000px;
    flex: 99;
    overflow-y: scroll;
    .go{
        height: 36px;
        width: 90px;
        border-radius: 18px;
        background-color: #fff;
        position: fixed;
        text-align: center;
        line-height: 36px;
        top: 60px;
        right: 15px;
    }
    .advert{
        width: 100%;
        font-size: 46px;
        font-weight: 700;
        color: #fff;
        position: fixed;
        text-align: center;
        bottom: 150px;
        // 透明度为0 - 不显示
        opacity: 0;
        // 引入动画
        animation: single 4s linear forwards;
    }
     /* 定义广告语动画 */
     @keyframes single{
        0% { 
            opacity: 0;
            bottom: 150px;
        }
        50%{
            opacity: 0.4;
            bottom: 120px;
        }
        100% {
            opacity: 1;
            bottom: 100px;
            
        }

    }

}